87 DT200 shifts in and out of grear

[nskifac]

I'm new to the boat and motor. After a long battle with the fuel system (poor storage from previous owner) I find that at idle in neutral the motor is shifting into forward and reverse on it's own. Where should I begin? Are there linkage adjustments? Thanks for your help.

[JUST-IN-TIME]

yes you adjust it on the motor